Healthy Living Articles

Got Vinegar...for blood sugar lowering?

Ryan Bradley, ND, MPH

October 2013

As most regular readers know, I am committed to helping people with diabetes find safe, non-drug approaches to lowering their blood sugar. One promising and simple approach is the use of vinegar in food, or used as a supplement to diet, physical activity and stress management. But is it really as easy as taking vinegar, or using more vinegar in food? How is it that this simple, inexpensive substance can be used this way? Well, in order to answer this question, I reviewed the scientific literature and provide a summary below of our current understanding. I hope you are inspired to leave the sweets behind and “go sour” instead!

Bread and Vinegar

One of the first studies to investigate the effect of vinegar on blood sugar was published in 1998 by Liljeberg et al. from the United Kingdom1. In their study, they randomly assigned healthy adults to one of two meals, a white bread challenge or a white bread challenge plus vinegar. The group also measured how quickly certain marker compounds entered the blood stream when administered with and without vinegar. Their results were notable in several ways: 1) Adding vinegar to the white bread challenge meal significantly reduced the average blood sugar concentration for several hours after eating; 2) Adding vinegar also reduced the insulin response after the challenge; and 3) the marker compound appeared in the blood more slowly with the added vinegar, suggesting the vinegar may work by slowing down how quickly food leaves the stomach (also known as “gastic emptying”).

Although this study was not performed in people with diabetes, it supports a basic mechanism of action of vinegar, which may be helpful to people with diabetes, and clearly demonstrated the concept that vinegar could be helpful to lower blood sugar after meals rich in high glycemic index carbohydrates (e.g., white bread).

What do we know about the actions of vinegar in people with diabetes? Keep reading!

Sweet… I mean… Sour Dreams

I first started paying attention to the evidence supporting vinegar for diabetes in 2007, when White and Johnston published a small clinical trial in Diabetes Care2. In their trial, participants with type 2 diabetes followed a standardized meal plan for two days, with and without taking 2 tablespoons of apple cider vinegar added at bedtime. The results of the study demonstrated morning fasting blood sugars were significantly lower when participants took the bedtime vinegar!

Interestingly, this study challenges the mechanism of vinegar’s effects since in the vinegar was not given at mealtime and yet still lowered blood sugar, suggesting an additional mechanism to delaying gastric emptying. The authors noted the basic science research of Fushimi et al., which supports an additional mechanism of vinegar - to increase glucose storage in the liver, and to increase the metabolism of fats 3,4.

Vinegar Gets Complex

Johnston et al. have continued their research of the effects of vinegar since their pioneering study in 2007. Additional research published in 2010 went on to clarify several remaining questions about the use of vinegar to lower blood sugar, including questions about dosing, timing of administration, and the influence of meal composition on the effects of vinegar5. In this study, vinegar was administered to a small group of people with diabetes, either as 10 grams of vinegar (approximately 2 teaspoons), 20 grams (approximately 4 teaspoons), or as an oral supplement of acetic acid (as sodium acetate). Groups were randomly selected to consume the treatment either with meals, or five hours before meals. The results of the study demonstrated several key findings: 1) Just 10 grams of vinegar significantly reduced blood sugar after meals by about 20%, whereas sodium acetate had no effects; 2) Vinegar was most effective at lowering blood sugar when it was taken with the meal; and 3) The effects seemed to be greatest when vinegar was taken with food that included more complex carbohydrates rather than just simple sugars (e.g., glucose itself), suggesting a potential effect on the digestion and metabolism of complex carbohydrates.

Also adding complexity (and clarity), are the results of research performed by Liatis et al. in 20106 In this research, 20 grams of wine vinegar was administered to a small group of people with type 2 diabetes with a meal containing high glycemic index carbohydrates, or with a meal containing low glycemic index carbohydrates (Note: glycemic index refers to the rate at which sugar enters your bloodstream after eating various foods; if it enters very quickly, the food is considered “high glycemic index” and if it enters slowly, the food is considered “low glycemic index”.) Their findings suggested that vinegar is only effective at reducing blood sugar following the consumption of high glycemic index carbohydrates.

A Fly in the Vinegar?

To be fair, not all of the research on vinegar supports its benefits for reducing blood sugar after meals. A brief report of research published by van Dijk et al. in 2012 compared the effects of 25 grams of white vinegar administered with a 75 gram oral glucose tolerance test, and found there was no difference in blood sugar after the test with vinegar, versus without 7. Although initially this result seems inconsistent, the findings are actually consistent with the work of Johnston et al. in which they found vinegar did not work with simple sugars (e.g., glucose in an oral glucose tolerance test) but rather seemed to be effective only when more complex starches were consumed.

In a Pickle…

…over what to do about your blood sugar? Although it is admittedly an acquired taste, adding (or taking) vinegar may help lower your blood sugar and reduce your need for added medications. However, if your blood sugar is not well managed, I would not advise you to spend months and months on a trial of vinegar to see if it may be helpful, but I do think it is safe, and potentially effective, enough for a personal experimentation.

There are several approaches worth trying. The easiest, although not necessarily the most effective, is to take 2-3 teaspoons of apple cider vinegar at bedtime and carefully monitor your fasting blood sugars in the morning; if they seem to be trending downward, continue the experiment. One caution, if you take medications known to cause hypoglycemia (e.g., insulin and sulfonylureas like Glipizide® or Glyburide®) you may want to begin with a lower dose and increase your dose over time after you have had a chance to observe the effects.

An alternative experiment is to be sure to either include vinegar in starchy foods, or take vinegar with starchy meals. This approach requires being more disciplined and perhaps even carrying a small bottle of vinegar with you for those meals out, however based on the available data, this approach may reduce your blood sugars after meals the greatest amount (i.e., up to 20% lower). Again, be cautious if you take insulin (especially mealtime or “bolus” insulin) and/or sulfonylureas due to the potential increased risk of hypoglycemia.

If you get a chance, please send me some feedback on your personal experiments trying vinegar - I am interested to know your results. In the meantime, pucker up!

In health, Ryan Bradley, ND, MPH

Ryan Bradley, ND, MPH is a naturopathic doctor, clinical researcher and epidemiologist in San Diego, CA. He is Assistant Director of Research at the National College of Natural Medicine in Portland, OR. In addition to his research, he is a practicing clinician specializing in natural and integrative approaches to treating type 2 diabetes, chronic kidney disease and heart disease at Pacific Pearl La Jolla.

Fushimi T, Sato Y. Effect of acetic acid feeding on the circadian changes in glycogen and metabolites of glucose and lipid in liver and skeletal muscle of rats. The British journal of nutrition 2005;94:714-9.